Safety-valve.



No. 643,239. Patented Feb. I3, 1900.

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SAFETY VALVE.

(Application filed July 10, 1890.

(No Model.) 2 Sheets-Sheet l.

rre TAJTES F F ICE.,

PATENT SAFETY-VALVE.

srnorrrearron forming part of YLetters Patent No. 643,239, dated February 1s, 1900.

Application filed J'uly l0, 1899.

To all w/wm it may concern:

Beit known that I, FRANK SCHREIDT, a citizen of the United States, and a resident of Man seld,in the county of Richland and State of Ohio7 haveinvented certain new and useful Improvementsin Safety and Relief Valves, of which the following is a specification.

My invention relates to improvements in safety and relief valves. Its object is to provide safety and relief valves in which the main valve is held to its seat by pressure of steam and its opening and closing controlled by an auxiliary valve which is set to open when the pressure exceeds a certain limit, and which have no packed joints. This object is attained by the means described in the annexed specification and illustrated in the accompanying drawings, in which- Figure l is a central vertical longitudinal sectional view of a safety-valve embodying my invention, the lifting-lever, springs, auxiliary valve, and regulating screws being shown in elevation. Fig. 2 is a vertical transverse sectional view of the shell,taken through linemof Fig. l, the main and auxiliary valves having been removed therefrom. Fig. 3 is a central horizontal sectional view taken through the case upon line y y of Fig. 1, the parts having been removed therefrom,as in Fig. 2. Fig. 4 is a view similar to Fig. l of a relief-valve embodying my invention. Fig. 5 is a central transverse View of so much of the same as is necessary to show the handlever for lifting the auxiliary valve from its seat.

Referring to Figs. l to 3, the cylindrical case A for inclosing the main valve B consists of a cup having wings b upon the bottom, a lower beveled edge b to fit the valveseat a, and an annular rim b2 around the upper edge to t snugly against the interior of the case, and the auxiliary valve O has a lower interior screw-threaded extension a for attachment to a steam-boiler or other receptacle for compressed fluid, a lateral interiorly-screW-threaded extension a2 to be attached to an exhaust-pipe, and an upper eX- tension c3 for inclosing the trigger-valve D. A cup c, within which the auxiliary valve O reciprocates and against the perforated bottom c' of which the valve seats, has an eXterior screw-threaded collar c2 to iit into the case A, so that its enlarged bottom c seats against the annular rim a4 of the case, leaving a cham- Serial No. 723,271. (No model.)

ber d5 between the auxiliary valve C and the main valve B, which are held to their seats when no steam is in the boiler by a spring b3. The lower end of the cup c is reduced between the bottom c and the collar c2 to form a chamber c3, communication between which and the interior of the cup is made byperforations c4 in the walls of the cup. of the caseA is closed by a screw-cap a6.

The case A is perforated on the side vertically above the extension ct to form a seat cl for the trigger-valve D, which is held to the seat by a spring d', the tension of which is regulated to the point at which the pressure in the boiler is to be relieved by a cap-nut d2, which may be raised or lowered within the upper interiorly-screw-threaded end of the extension c3 by loosening the set-screw d3 and turning the key d4, which ts loosely upon the end of the extension and has a square perforation to fit the square end d5 of the capnut. After the desired tension of the spring is obtained the key is locked by setting the screw into one of the dents or depressions c? upon the exterior of the extension c3.

Upon the top of the case is a longitudinal by-pass as, which after the trigger-valve has been thrown from its seat passes the steam through the perforation a9 in the case into the end of the case A in upon top of the piston c5, which terminates the end of the valve-stem cG of the auxiliary valve C, which is thrown from its seat by the steam-pressure, since the area of the piston c5 is larger than that of the valve C. The steam in the chamber a5 then passes into the chamber c3, then through a perforation 01.10 into a by-pass a, which is situated upon the side of the case A, and from there through a perforation w12 into the exhaust c?. As soon as the pressure in the chamber d5 is reduced the main valve, previously held to its seat by the pressure of the steam in the chamber c5, is raised by the steam upon the inner edge of the rim h2 of the main valve.

Upon one side of the extension a3 of the case is a vertical by-pass otlwhich leads down into the exhaust c2 and communicates with the upper extension c3 of the case below the flange d6 of the trigger-valve by perforations d and a. The outer beveled edges of these perfor-ations seat screws al and all, by which the time of blow-off of the valve is regulated.

One side of the extension a3 has an annular ange al@ to pass the arm e of thehand-lever The end IOO E, which is cut out at the inner end to fit under the flange d6 of the trigger-valve D. The arm e is held rotatably in place by a pin e', which passes through a perforation in the iiange als and a slot e2 upon the arm e.

In Figs. 4 and 5 my invention is shown as applied to a relief-valve. The lateral extension f of the case F for inclosing the main valve G, which is of the same form as the main valve B, is to be attached to the end of a steam-engine cylinder, the downward extension f to an exhaust-pipe, and the lateral extension f2 is interiorly screw-threaded to receive a case I-I for an indicator. Into the upper interiorly-screwthreaded end f3' is screwed a cylindrical case R, so as to leave a chamber f4 between the main valve G and the end r of the case, which is perforated to seat an auxiliary valve r, whose stem r2 projects downward and terminates in a piston r3, which extends to within a short distance of the bottom of the valve G. The case R has perforations r4 in its walls, opening into an annular chamber f5 between the case R and the case F. A vertical by-pass f6 upon the side of the case F forms communication between this chamber and the exhaust f below the valve-seat. A pin r5 passes through the walls of the valve G and through the piston @-3 by a hole r, made oblong, so as to allow the piston to have a slight vertical motion independent of the valve. The valve has perforations g in its walls near the bottom, so that if there be water in the end of the cylinderl it will be forced into the valve by the enginepiston beneath the piston r3, throw it upward, and raise the auxiliary valve from its seat. The pressure of the steam in the chamber f4 being reduced, the valve G is thrown from its seat by the pressure on the under side of the rim g' of the valve. The case F also has a hand-lever, similar in construction to the lever E, for raising the valve r from its seat.

What I claim isl. In safety and relief valves the combination of a case, a main valve seated therein so that steam from the boiler or cylinder surrounds it, an auxiliary valve to be unseated by the fluid when its pressure exceeds a certain limit, a chamber between the valves the pressure of steam within which holds the main valve to its seat until the opening of the chamber by the unseating of the auxiliary Valve, substantially as shown and described.

2. In safety and relief valves the combination of a case having an extension to be secured to aboiler or an engine-cylinder and a second extension to be secured to an exhaust, a main valve within the case seating outward against the exhaust-opening consisting of a cup having a rim around its edge to iit snugly against the inside walls of the case, the cup or cylinder screwed into the case leaving a chamber between it and the main valve, the auxiliary valve seated against the end or bottom of said cup or cylinder to be unseated by the steam when it exceeds certain pressure, and the by-pass connecting said chamber with the exhaust when the auxiliary valve is unseated by the steam, substantially as shown and described.

3. In'a safety-valve the combination of a case having an inlet extension to be secured to a boiler and one to be secured to an exhaust, a main cup-valve within the case seating outwardly against the exhaust-opening and having a rim around its edge to iit against the inside walls of the case, a cup screwed into the case leaving a chamber between it and the main valve, an auxiliary valve seated against the perforated bottom of said cup and having a stem extending into the cup and terminating in a piston, a trigger-valve seated against a perforation in the case above the inlet, an adjustable spring for holding said valve to its seat, a by-pass for conveying the steam in upon top of said piston to unseat the auxiliary valve when the triggervalve is raised, and a by-pass for conveying the steam from said chamber to the exhaust when the auxiliary valve is unseated, substantially as shown and described.

4. In a safety-valve the combination of a case having a lower inlet extension for connection to a boiler, a lateral extension forcennection to an exhaust and an upper extension to contain a trigger-valve, a main valve and an auxiliary valve seated in the case having a chamber between them, a triggervalve seated against a perforation in the case above the inlet extension, a spring for holding the trigger-valve to its seat, a by-pass for conveying the steam in upon the auxiliary valve to unseat it when the trigger-valve is raised, a by-pass for conveying the steam from said chamber when the auxiliary valve is unseated, perforations in the side of the upper extension of the case to scat screws, and said screws by which the time of blow- 0E of the valve is regulated, substantially as shown and described.

5. In a safety-valve the combination of a case having a lower inlet extension for connection to a boiler, a lateral extension for connection to an exhaust and an upper extension to contain a trigger-valve, a main valve and an auxiliary valve seated in the case having a chamber between them, a triggervalve seated against a perforation in the case above the inlet extension, a spring for holding the trigger-valve to its seat, a by-pass for conveying the steam in upon the auxiliary valve to unseat it when the trigger-valve is raised, a by-passlfor conveying the steam from said chamber when the auxiliary valve is unseated, and a hand-lever for unseating the trigger-valve, substantially as shown and described.

, FRANK SCHREIDT.

Witnesses:

L. P. BENNETT, OHAs. E. SCHREIDT.

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